The present invention relates an etching processing method; and, more particularly, it relates to an etching processing method that is capable of decreasing the amount of particle contaminants and reducing the production cost.
For etching processing of insulation materials of low dielectric constant, for example, OSG (Organo-Silicate Glass), which is an inorganic insulation material of low dielectric constant doped with methyl groups, U.S. Pat. No. 6,362,109, for example, discloses an etching method which utilizes reaction gases mainly comprising fluoro carbons as a way of applying an oxide film etching technique.
When etching processing is conducted by utilizing reaction gases mainly comprising fluoro carbons, a reduction of the production cost becomes difficult, since the carbon ratio contained in the reaction gas is high, and the bias power to be applied to the wafers is increased. That is, since a high bias power is applied to the wafers, a power supply capable of supplying high power is necessary.
Further, in order to remove large amounts of input heat along with application of the high bias power, a chiller having a high cooling performance is necessary. Further, the withstand voltage of the components constituting the etching apparatus has to be increased, which increases the initial cost, and further increases the overall cost of the etching apparatus. Further, in the case where wafers having a large diameter, such as 300 mm, are processed, since the area of the chamber wall, which serves as the ground, is relatively decreased, the plasma potential fluctuates greatly by the bias voltage, and the chamber wall is consumed as it is subjected to sputtering. Accordingly, the chamber wall has to be replaced frequently, which results in an increase in the running cost.
Further, in a case of using inexpensive aluminum that has been subjected to alumite processing, which has generally been used as the material for the chamber wall, the aluminum material is exposed by abrasion of the alumite caused by the sputtering effect, in which aluminum fluoride, that is formed in the reaction between aluminum and fluorine, forms particles under the sputtering effect, thereby to lower the yield in the processing.
Further, when a gas having a high carbon ratio is used as described above, the deposition is caused in a chamber region where the plasma sputtering is weak. Accordingly, this frequently requires plasma cleaning or wet cleaning, involving opening of the chamber to the atmospheric air, which lowers the throughput.
Further, in the etching processing utilizing the reaction gases described above, fluoro carbons having a high carbon ratio, such as C5F8 have often been used. However, since these gases are special gases, they require high production cost, which results in an increase in the running cost.